Moving-lens cinematograph apparatus



23 9 E232@ Ll- Q CAMPBELL ET M MOVING LENS CINEMATOGRAPH APPARATUS Filed Dec. 20, 1925 nnnmnmmmmmmmmmmmuuom ATT ma N Enr.

Patented Feb. 23, l 1926.

l-JNl'l-'su'v 'STATE-s CHARLES WILLIAM nnA CAMPBELL, or'nnmnonx, AND rmx come Bonnnrs, or JCHANNESBURG, rnANsvAAL, soU'rn AFRICA.

MOVING-LENSCINEMATOGBAIPH APPARATUS. i

Application led December 20, 1923. Serial No. 881,683.

To all 'wlwm it may concern? Be it known that CHARLES WILLIAM REA CAM'PBELL, Briti'shsubject, and FRANK GowYNE ALFRED'RQBEBTS, British subject, re-

siding at care of Victoria Falls & Transvaal Power Co. Ltd.,'Driehoek, Transvaal, and Stoneycroft, corner of 3rd `and 6th Avenues, Rosebank, Johannesburg, Transvaal, Union ofl South Africa, respectively, have invented certain new and useful Improvements in Movin -Lens Cinematograph Apparams, of .Whic the following is a specitication. .The present invention has reference to cinematograph apparatus of the kind em-A ploying an endless moving series of connected lenses, which, for instance, co-operate with a continuously moving lm and an o tical correcting means as described 1n t e specification of our prior Patent No. 1,486,- 362. v

Thev invention provides a resilient vmetallic or like band on which the lens series is mounted and which is arranged to, be guided in a straight path, durin exposure, stably and with the minimum o friction.

The invention also' provides a lens. band' with lenses-fixed thereon at intervals which can effectively engageadriving or supporting drum havingfaV circulary eriphery.

The invention is illustratev in the accompanying drawingsin which: 4 Fig. is a front view of a lens-series for Aa projector' or camera.. f ig. "II is a` plan sectioned on II-II 5 ig. III is a front view of the lens band. 'Fig. IV is` an enlar ed' cross sect1on through IV-IV Fig.

- Fig. V is fa diagram. i

itis desiredto move through a zone A with true rectilinear motion and at a .definite linear speed. According to Athis invention the lenses-2 arenfor this pur ose mounted upon an endless thin and resilient band 3, conveniently a metal band.

Inorde'r to p zone A of the and where the lenses are to be operative, with reasonable bending force von the 'band and resulting friction, advantave ,is taken of the fact that if an endless thin spring band Aof initially circular form 2 indicates an endless ser1es of lenses which B, Fig. V has one part of itconstrained, for instance, at the point C, and another point D of it is pressed inwards, a position is reached where there forms about the ressedin.point a zone A which is straight or some distance and gradually merges 'into the curved remainder of the band; the extent of the zone de ending upon the 'length and stiffness of t e band.

This arran ement is carried ont in the Construction s own by placing at the point C the roller 4, which may b e adjustable, and making gate guide 5. Y

yThe active surface 6 ofthe gate guide touches the outside face of the band, no corresponding inner guide being necessary.

Said surface is preferably formed as twov narrow strips (Fig. I I) touching the band the `point D the centre poi'nt of al immediately on either side of the 'lens mounts 7 arranged in the centre of the band, the

.borders-of the band being :left free in the gate guide..

By arranging the points C and D at diametrically o posite of the. band the flattening o the band is effected with Vthe least possible forceand resulting friction. The relative positions ofthe constraining points mayhowever varied-and the point C -ma be vdu licated; but the nearer the point is to t e other constraining point or points themore force is necessary to Aflatten the bandand the lessthe length of the attened zone. A

- The resilience of the hand holds it in good Contact with the guide surface -6 and resists any force tending to displace theband from that position, so thatthe lenses in the z one A are ve stably held in a straight line. A Sproc et drum 8 is'arranged to engage part of the curved section of the'band for supporting and driving the same.-

The attachment of the rigid lens mounts 7 atv intervals alo the band produces in the band alternate rigid sections Sand non-` rigid sections 10 so that the band inpassing V Varound the drum 8 necessarily assumes a roduce the truly rectilinear roughly polygonal form. The mounts 7 are accordingly attached atY theA centre of the band as shown in Fig. III and the band is made of such width in relation' to its thickness that the borders 11 of the band can, in

les

passing around the drum,retain' a circulan iorm; the intermediate widths 12 of the band resiliently buckling to accommodate the circular and the polygonal forms.

The drum 8 engages the band only' at the borders'll and is' made of large diameterin order to minimize the diierence between the circular'and polygonal forms of the band.'

.A band varranged as described and engaging with Vthree pairs ci s rockets on Lthe drum 8 by aretaining-rol er 13 is amply rigid in the plane of its edgeand requires no edge' guiding.

The lens mounts-7 may be fired te the bandas shown in Fig. TV by forming at the base of each a circular spigot le which passes into a hole l5 in the band? andisthere secured by a screw i6.

lso

band embodying'tlie alcove features has operatedsuccessiully when constructed and etteeth. L'We claim 1. The combination of a thin spring band of naturally circular'form, a series of lens mounts thereon, means constraining' `one part ofthe band against outward movement,

vy means constraining the band at another partv by inward pressure only to formt a natural straight` section at said other vpart,"and' v means for driving the band.

2. The combinativ n 'of a thin resilient band of naturally circular form, a series of lens mounts thereon, means pressing said band inwardly at substantially diametrically opposite points to form a natural straight section, and means for` driving the band.

3. `The combination of a thin vresilient band of naturally circular form, a. series of i lens mounts thereon, a rectilinear guide engaging the outside of the band, means constraining the opposite side of the band'b'y inward pressure to cause the same to conform to the rectilinearguide, and means forv driving the band. .s v

4. The combination of a thin resilient band of naturally circular form, a series of lens' mounts thereon, means constraining part of the band against outward movement.

-means constraining another part of the band by inward pressure toshapefthe bandinto' astraight part and Vcurved parts, and a grivng drum engaging acurved-part-of the an y 5. The combination of `a thin resilient endless band, a series oflens mounts there-v on, a drum engagingthe border area of thel intervals along a stri o rily the'inner area of the band'.

7. The' combination of a thin endless band, a series oi lens mounts arranged at intervals along the centre strip thereof thereby rendering inexible successive portions'o'l said strip and leaving iiexible portions of the strip between the inflexible portions, the borders of the band beingv unoccupied. by the mounts and tlie/ band being suliciently exilole transversely 'to permit the borders te fier: to circular form Whilst -the centre strip :tienes as necessitated by its inexilole portions, and drum having a circular peripheryl engaging only the borl Y ders of the band.

8. lllue combination of a thin endless band, a series of lens mounts arranged at comprising part of the width of the ban and thereby rendering inflexible successive portions ot said strip andleavng flexible portions between said inflexible portions, a further part of the width of. the band being unoccupied by the lens mounts, and the band being suiliciently flexible transversely to permit said further part of the width to flex to lcircular form whilst the strip holding the lens mounts ilexes to the form necessitated by its inflexible portions and a drum havinga'circular periphery which engages only that portion of the width of the band capable of assuming the circular form.-

9. The combination of a thin endless band, a series of lens mounts arranged at intervals along a strip com risingonl part of the width of the band t ereby ren ering inflexible successive portions of said strip and leaving liexible portions between said inflexible portions, the remaining width of the band. being unoccupied by the lens mounts andthe band being of such flexif bility transversely that when the band is flexed, the form assumed by the unoccupied width of the band -is not materially inluence'd by the form imposed on the mountl containing strip by reason of its inflexible portions.

10. The combination lof a thin endless i spring band, a series of lens mounts arranged at intervals along a strip comprising only iiexcd, the form assumed by the unoccupied width of the band is not materially influenced by the form imposed on the mountcontaining strip by reason of its inflexible portions.

l1. The combination of an endless band of thin s ring metal of such relative Width and thickness that the borders can curve to circular form Whilst the ycentre* strip vassumes a roughly polygonal form, a number of lens mounts fixed at intervals to the centre strip and thereby renderingr inflexible successive portions of said strip, means constraining said band into a form comprising two oppositestraight lengths and curved upper and lower ends. said means Vcomprising a linear guide touching the outside of one straight strip, and a member touching the outsideof the other straight strip, and a drum having a cylindrical periphery engaging only the edges of the band in the upper curved portion.

In testimony whereof We have hereunto set our hands.

CHARLES WILLIAM REA CAMPBELL. FRANK GOWYNEALFRED ROBERTS. 

